1. Field of the Invention
The invention concerns a personal electrocardiology recorder for detecting heart action signals.
2. Description
Electrocardiology tape recorders are used to detect and record or store heart action signals, more particularly in the supervision of patients and for stress tests in occupational and athletics medicine. The systems used differ fundamentally from one another in some respects, depending on their intended use and the aim of the supervision.
Tape recorders which are worn by a patient or subject and which are connected to the patient's skin by conventional body electrodes are known. Depending upon the kind of supervision required, recorders of this kind can record heart action signals for a specific time, as a rule 24 hours, on magnetic tape. Recorders of this kind are named after the pioneer in this area, Dr. N. Holter. In order to reduce the complexity of evaluating recordings, systems of this kind have been developed so that the recorder becomes actuated only in response to particular phenomena such as cardiac arrhythmia or the recorder switches itself on automatically at preselected time intervals. This enables the duration of use to be increased to up to 72 hours. It is usually impossible to extend this time any further since at that time the electrode contact on the patient's skin must be renewed by skilled personnel.
The evaluation of the taped electrocardiographs is usually carried out by the physician using a special evaluator in which the taped recording is displayed optically on a viewing screen and/or is transferred to paper.
Another system widely used in the United States of America is telephone ECG or EKG supervision. In response to the onset of a symptom such as cardiac arrhythmia, the patient gets into direct phone communication with a recorder in his physician's premises in order to phone in his heart action signals being monitored by a portable ECG amplifier. In a further development of this system, the ECG amplifier has a short-term storage capability which serves for the temporary storage of the signals, so that there ceases to be any need for a telephone to be immediately available. Facilities of this kind are of use only where there is a corresponding telephone transmitting, receiving and recording system. At present this is limited to the United States of America. Furthermore, transmission by telephone greatly restricts the accuracy of the recorded ECG.
Consequently, a simplified narrow-band ECG amplifier having more particularly a simplified electrode arrangement can be used. Equipment has therefore been proposed in which the electrodes are disposed directly on the ECG amplifier casing. Possible disturbances by the electrodes being spaced close-together are insignificant in view of the low quality of the transmission system.